Enhance merge maneuver type assignment

[dgearhart]

Issue

While testing the OSRM compatibility mode - noticed some inconsistent assignments for the merge maneuver type. Added logic to provide consistent assignments.

Example 1
< BEFORE
< Continue on 17th Street.
> AFTER
> Merge onto 17th Street.

Example 2
< BEFORE
< Continue on PA 743 North.
> AFTER
> Merge onto PA 743 North.

Example 3
< BEFORE
< Merge left onto US 220 Business
> AFTER
> Turn left onto US 220 Business

Tasklist

• Test
• Review - you must request approval to merge any PR to master
• Generally use squash merge to rebase and clean comments before merging
• Update the changelog